Control device



Nov. 12, 1940. R w @CFF 2,221,324

CONTROL DEVICE Filed Apri129, 1959 F .1 F .2. '12 1,7 4 a s Q 50 '12 9:

A WNIHW! ibo u mul Inventor. Rcpbert, W. GOFF, by His Attorneg.

m''lllllllll Patented Nov. 12, 1940 UNITED STATES coN'raoL DEvIcE RobertW. God', Schenectady, N. Y., assigner to General Electric Company, acorporation of New York Application April 29, 1939, serial No. 270.881

' 1o claims. (ci. zoo- 47) My invention relates to control devices, moreparticularly to mechanical limit switch devices adapted to perform anelectrical switching operation after a predetermined travel of a drivenmember, and has for an object the provision of a device of thischaracter which is simple, rugged and reliable, and which will notbecome jammed or damaged through overtravel of its driving means.

My invention is particularly adapted to limit switches and similar timeinterval control devices for controlling reversible motors or machines.For use in the control of metal-Working machinery, such as, planers,successive switching operations may be performed after predeterminedoperation of the machinery. If desired, a single switching operation maybe performed after the operation of the controller is initiated, and,thereafter, a second switching operation may be performed after theinitiation of a second operation of the controller, and so on. vThislatter type of control is useful in the automatic opening and reclosingof motor-operated doors.

One of the important features of my invention is the provision of atraveling means which operates the switching means, and immediately isinposition to operate again without requiring resetting or readjustment.This traveling means is readily adjustable to provide a variety ofcontrol operations, and for reliable operation, is positively associatedwith its driving means at all times, no reliance being -placed onsprings or resilient connections for either driving or resetting. Thecontrol device embodying my invention is inherently free from damage toits parts by jamming or otherwise upon overtravel of its driving means,in spite of the aforementioned positive association of the driving meansand the traveling timing means for reliable operation.

In accordance with my invention,.I have pro-l vided a controller havingsuitable driving means, such as, a driving gear, which is operated bythe motor or machine to be controlled, either directly or through asuitable connecting device. Means including'a pair of traveling pinionsmeshed with the driving gear are mounted on a threaded member fortranslational movement thereon, the traveling pinions being drivenforward or back- Ward along the mounting member in respectively the samedirection in a denite angular and spaced relationship. Depending uponthe direction of translation, the leading one of the traveling -pinionsengages and rotates one or the other of a -pair of operating membersmounted on unthreaded portions of the mounting member.

Pins which engage with each other are provided for this purpose on thepinions and operating members, and are disposed in predetermined angularrelationship.

Essentially, the operating members comprise a' cam part for actuating asuitable control switch to control the motor and a gear part having afew gear teeth omitted. The space provided by the missing teeth is innormal registry with the driving gear so that the operating member isnot rotated until engaged by its traveling pinion. Thereafter, the gearpart of the operating member meshes with the driving gear for rotationthereby until the driving motor stops or reverses.

To protect the controller from damage by jamming of the travelingpinions against the operating member if the driving motor overruns, thenormally stationary mounting member is rotatable by the operatingmembers. This rotation of the mounting member is eiected byco-operating. projections on the operating members and mounting memberengageable to rotate the mounting member after a 4predetermined rotationof the operating members. In this manner, simultaneous and like rotationof the mounting member and the traveling pinions prevents furthertranslational movement of the traveling pinions, although rotation ofthe driving gear is continued.

In operation, the driving gear is driven by the motor to be controlled,andthe motor operates -until the two traveling pinions are translatedalong the stationary -mounting member far enough for the leading one tohave its pin engage the pin on the corresponding operating member. Thegear part of the operating member is then meshed with the driving gearand the cam part operates its corresponding switch. ThenI the drivingmotor is stopped or reversed as the case requires. When the motor anddriving gear is operated in the reverse direction, the traveling pinions`move in the opposite direction retaining,

of course, their predetermined angular and spaced relation, until thepin on the traveling pinion now leading engages the pin on its operatingmember for actuating the corresponding switch. The length of the path oftravel or translational movement of the traveling pinions between theirrespective control positions is the determinant of the time of control.By changing the spacing between the traveling pinions so that their pathof travel is increased or decreased, the control is correspondinglyadjusted.

Further objects and advantages of my invention will become apparent inthe following speciiication, and for a more complete understanding of myinvention reference should be had to the accompanying drawing in whichFig. 1 is a plan view of a controller embodying my invention; Fig. 2 isa sectional view taken along the line 2-2 of Fig. 1 lookingin thedirection of the arrows; Fig. 3 is a sectional view taken along the line3-3 of Fig. 1 looking in the direction of the arrows; Fig. 4 is asectional view taken along the line 4--4 of Fig. 1 looking in thedirection of the arrows; Fig. 5 is a fragmentary view partly in sectionof a detail of the controller embodying my invention; and Fig. 6 is acircuit diagram showing the controller connected to control a pair ofelectric motors.

Referring now to the drawing, I have shown my invention in one form as alimit switch for use in the control of planer motors or the like. Theoperating mechanismof the switch is enclosed in a suitable insulatingcasing IIJ or, if desired, in a metal casing provided with a cover I Isecured bythe screws I2. 'I'he motive force of the motor controlled issuitably applied to a driving means in the switch. This vdriving meanscomprises a long driving gear I3 which is journalled in the walls of thecasing I0 and which drives means for operating a switching means in amanner described hereinbelow.

The switch operating means comprises a pair of traveling pinions I4 andI5 mounted for rotation and translational movement respectively in thesame directions along the threaded portion of a mounting member or screwshaft I6. 'I'he traveling pinions I4 and I5 are meshed with the drivinggear I3 and threaded back and forth along the normally stationarymounting member I 6 between a pair of operating members I1 and I8 eachof which is rotatable upon engagement by the leading one of thetraveling pinions. At one end of the path of travel, a pin I9 on thetraveling pinion I4 engages a pin 20 on the operating member I1 and atthe other end of the path of travel, a pin 2| on the traveling pinion I5engages a pin 22 on the operating member I8 for rotating these-members.

The operating members I1 and I8 are rotatable on unthreaded portions ofthe mounting member I6. These members are identical and comprise thecams 23 and A24 and the operating pinions 25 and 26, the respective camand operating pinion of each being` integrally secured in axial relationfor rotation on the mounting member I6. The pinion 25 of the operatingmember I1 carries the pin 28 on its inner side facing the travelingpinion I4 and its pin I9, and the pinion 26 of the operating member I8carries the pin 22 in a similar relation to the traveling pinion I5 andits pin 2|. The operating pinions 25 and 26 are preferably of the samediameter as the travelingv pinions I4 and I5 and are provided with thespaces 25a on their peripheries form which a few gear teeth have beenomitted. The spaces 25a,

formed by the missing gear teeth are in normal' registry with the longdriving gear I3 so that the operating pinions 25 and 26 will not berotated thereby, the driving gear I3 extending adjacent the pinions 25and 26 in parallel relation with the mounting member I6. When, however,either of the operating members I1 or I8 is turned slightly by itscorresponding traveling pinion, the operating pinion 25 or 26 mesheswith the driving gear I3 and is driven thereby. Rotation of theoperating pinion 25 or 26, of course, rotates its respective cam 23 or24 which in turn actuates the switching means.

'I'he switching means comprises the pivoted switch arms 21 and 28mounted on the ends of a rod 29 supported by the casing I0 and securedtherein by a clamp 30 at the center. A pair of springs 3l and 32 serveto bias the switching arms 21 and 28 into respective engagement withtheir cams 23 and 24. The switch arms 21 and 28 are rotated respectivelyby the cams 23 and 24 for operating the respective movable contacts 33and 34 carried at the forward end of the pivoted arms. As shown, themovable contacts 33 are of the spring-mounted bridging type and arenormally open and operated to engage the fixed ccntacts 35 when the arm21 is rotated clockwise (as viewed in Fig. 2) from its normal position.The movable bridging contacts 34 are normally closed and operated todisengage the fixed contacts 36, when the arm 28 is similarly rotatedfrom its normal position. Connecting the iixed contacts 35 and 36 in thecircuits to be controlled are the conductors 31 which are led out of asuitable opening in the front wall of the casing.

To prevent jamming of the controller after a. predetermined overtravelor overrunning of the driving gear I3, means are provided for rotatingthe normally stationary mounting member I6. Frictional bearings 38support the mounting member I6 at each end. the mounting member beingsecured by the clamps 39 and the springs 40 against normal rotation.Near the ends of the mounting member I6, the hubs 4I and 42 are providedhaving the projections 43 and 44 which are engaged by the pins 45 and 46extending respectively from the outer faces of the cams 23 and 24. Aftera predetermined rotation of one of the cams 23 and 24, the pin 45 or 46engages its hub 4I or 42 and the mounting member I6 is rotated inaccordance with the angular movement of the driving gear I3, the hubs 4Iand 42 being secured to the mounting member I6 by the pins 41. Rotationof the mounting member I6 by the driving gear I3 at a predetermined rateprevents further translational movement of the traveling pinions I4 andI5,.and as will be more fully described hereinafter, damage tothecontroller by overtravel of the driving gear I3 cannot occur.

In operation of the controller, the length of the path of travel of thetraveling pinions I4 and I5 may be adjusted by loosening the clamps 39on the mounting member I6. The springs then cause the mounting member I6to rise in the casing I Il for enabling manual rotation of the travelingpinions I4 and I5 independently of the driving gear I3. One or both ofthe traveling pinions I4 and I5 is threaded on the mounting member I6 tothe'desired position. Then the traveling pinions are re-engaged ormeshed with the driving gear I3, but in a predetermined angularrelation, so that the pins I9 and 2l carried by each will registerrespectively with the pins 20 and 22 on the operating members I1 and I8when the traveling pinions are driven to their operating positions.

From a starting position, preferably with the pin 2| of the travelingpinion I5 in engagement with the pin 22 of the operating member I8, thedriving motor is operated to drive the driving gear I3 in acounter-clockwise direction as viewed from the right hand end in Fig. l.The traveling pinions I4 and I5 are rotated clockwise on the mountingmember I6 and translated from right to left thereon. After a.predetermined travel, the pin I9 engages the pin 20 and the operatingvbeing moved out of registry with the driving gear.

Rotation of the operating pinion 25, of course, causes like rotation ofthe' cam 23 which forms a part of the operating member I1. As viewed inFig. 2, counter-clockwise rotation of the cam 23 causes clockwiserotation of the switch arm 21 onits rod 29, and the normally-opencontacts 33 and 35 are engaged.

Engagement of the contacts 33 and 35 may cause immediate reversal of thedriving motor so that the driving gear,i3 is rotated in the oppositedirection, namely, clockwise as viewed from the right hand end inFig. 1. Thereupon, the operating member I1 and the traveling pinions I4and I5 are rotated counter-clockwise, the driving gear I3 positivelydriving the operating pinion 25 until the space 25a registers with thedriving gear and rotation of the operating member I1 ceases. The cam 23again enables the switch arm 21 to place the contacts 33 and 35 in thenormally-open position, the spring 3l appropriately biasing the switcharm 21.

Continued rotation of the driving gear i3 clockwise causes the travelingpinions It and I5 to thread from left to right al'ong the mountingmember I6 until the pin 2i on the traveling pinion I5 engages the pin 22on the operating member I8. Operation of the normally-closed contacts 34and 36 to the open position occurs in a manner similar to that describedin connection with the operation of the contacts 33 and 35. Thus, thedriving motor may be stopped until it isI again desired to initiate thecontrol by operating the motor in the reverse direction. It will beunderstood, of course, that the motor may be made to operate and reversecontinuously or may be made to operate only for one cycle of operation.Therefore, I do not wish to be limited to the 'particular forward andreverse operation described herein.

Referring now to Fig. 2, the manner in which jamming or damage to thecontrolleris prevented may be described as follows. If the driving motorfails to stop or reverse in response to the operation of the controllingcontacts 33, 35 or 3d, 3E or if the control is effective but the motorovertravels due to its momentum, the driving gear I3 will continue todrive the operating member Il or i8 and the traveling pinions I and I5.Considering the left hand end of the controller, as seen in Fig. l andFig. 2, it appears that upon overtravel the traveling pinion I8 soonwould ride into the operating member l1 and jam against it. To avoidsuch an occurrence, sufcient spacing is allowed between the travelingpinion It and the operating pinion 25 to permit at least one fullrevolution of the traveling pinion It after its pin I9 engages the pin20 on the operating pinion. In this manner, because of a four to onegear ratio between the traveling pinions and driving gear i3, thedriving gear safely may make substantially three revolutions withoutcausing damage to the controller. Also, since the operating pinions 25and 26 and traveling pinions I and I5 are of the same diameter, theoperating member Il will make one revolution during four revolutions ofthe driving gear.

As seen in Fig. 2, when the operating member v Each contactor isnormally open when its I'I is turned counter-clockwise through slightlyless than one revolution by rotation of the driving gear I3approximately three revolutions, 'its pin I5 engages the projection 43on the hub 4I which is secured to the mounting member I6. `Immediatelythe mounting member I6 is rotated in the same direction and at the samespeed as the traveling pinions I4 and I5. Since, both the mountingmember I6 and the traveling pinions Il and I5 now are rotating as aunit, further translational movement of the traveling pinions I4 and I5cannot occur. Thereafter, the driving gear I3 may rotate indenitelywithout however, being opened and closed during cach revolution of theoperating member I1. In this 'damaging the controller, the contacts 33and 35,

manner, a predetermined factor of safety, in this instance. threerevolutions, is provided through which the driving gear I3 may turnwithout affecting contact operation, and thereafter the whole operatingmechanism operates, but without damage to itself.

After overtravel, when the .driving motor is finally stopped andreversed, the driving gear i3 drives the operating member I1 and throughit the hub 4I and mounting member I6 to their respective normalpositions, shown in Fig. l and Fig. 2. The space 25a in the operatingpinion v25 again registers with the driving gear I3 to prevent furtherrotation of the operating member Il, and the controller is ready foroperation vwithout further resetting or manipulation.

That is, the traveling pinions I6 and I5 may now be driven from left tovright to operate the operating member I8 and the contacts 36 and 36.

To illustrate the use of a controller embody- 'ing my invention in asimple circuit, I have shown in Fig. 6 a pair of driving motors M1 andM2 for driving a planer bed back and forth, each motor operating theplaner in one of the directions. If desired, a single reversing motormay be used instead, but that involves a reversing switch and additionalcontactors which, for vthe present purposes, would unduly complicate thecircuit. As shown, the motors M1 and M2 are supplied from suitable threephase power lines L1, L2 and L3. The motor M1 is switched by thecontactor 5l having the magnetic operating coil 52, and the motor Mz isswitched by the contactor 53 having the magnetic operating coil 5d.

respective magnetic coil is de-energized.

The controller or limit switch contacts 55 and 55 serve to de-energizethe magnetic coils 52 and 5d respectively at the end of thepredetermined working stroke of the planer bed, the contacts 55 of themotors M1 and M2 for operation therebyl vwhen. the particular 'motor isenergized.

The coils 52 and 54 are respectively energized from line L1 through asuitable three position switch 51 which may be hand-operated to a,neutral position as shown to de-energize the coils. If operatedcounter-clockwise, the switch 5l closes the circuit from L1 through thecoil 5d and the limit switch contacts 56 to line L2. If operated.clockwise, the switch 51 closes the ciraoy cuit from line L1 through thecoil 52 and the limit switch contacts 55 to line L2.

In operation, with the bed of the planer in some intermediate positionready to be moved; out to either end of its stroke, the switch 51 ismoved to one or the other of its circuit closing positions. If, forinstance, it is desired to operate the planer in one direction, theswitch 51 may be moved clockwise from its neutral position shown.Immediately the contactor coil 52 is energized, the contactor picks upand the motor M1 operates. The motor M1 drives the planer in the desireddirection and simultaneously drives thev operating mechanism of thecontroller to open the contacts 55 at the end of the predeterminedstroke. When the contacts 55 open, the coil 52 is deenergized and themotor M1 is disconnected.

The switch 51 may then be moved counterclockwise to energize the coil 54and thereby close the circuit to the motor M2 through the contactor 53.The motor M2 then drives the planer and operating mechanism in theopposite direction until the contacts 56 are finally opened andoperation discontinued. Although for simplicity I have shown the switch51 as a manually operated switching means, obviously automatic startingmeans for the motors may be used if continuous automatic operation isdesired.

While I have shown a particular embodiment of my invention, it will beunderstood, of course, that I do not wish to be limited thereto sincemany modifications may be made, and I therefore contemplate by theappended claims to cover any such modifications as fall within the truespirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. The combination in a controller of a travelling member mounted fortranslational movement, a driving member connected to said travellingmember to give said travelling member translational movement, anoperating member mounted in the path of translational movement of saidtravelling member arranged tobe driven by said driving member butnormally in disengaged relation with said driving member, said operatingmember being engaged by said travelling member and moved thereby intoengagement with said driving member for movement by said driving member,and'control means operated by said operating member.

2. 'Ihe combination in a controller operable to perform a controlfunction after a predetermined time interval of driving means includinga rotatable member, timing means including a pair of traveling membersdriven by said rotatable member, means mounting said traveling membersfor translational movement respectively in the same direction saidtraveling members being movable lon said mounting means in one or theother of two predetermined translational directions depending upon thedirection of rotation of said rotatable member means including a i'lrstand a second operating member operable by said traveling members, thefirst of said operating members being operated by one of said travelingmembers after a predetermined movement of said traveling members in oneof said predetermined translational directions, the second of saidoperating members being operated by the other of said traveling membersafter a predetermined movement of said'traveling members in the other ofsaid predetermined translational directions, and adjustable supportingmeans for said mounting means whereby said mounting means is movable tomove said travelling members out of driving relation with said rotatablemember thereby to provide for adjustment of said travelling members onsaid mounting' means for regulation of said translational movements ofsaid travelling members.

3. The combination in a controlleroperable to perform a control functionafter a predetermined time interval of driving means 'including arotatable member, timing means including a pair of traveling membersdriven by said rotatable member, means mounting said traveling membersfor translational movement respectively in the same direction, saidtraveling members being movable on said mounting means in one or theother of two predetermined translational directions depending upon thedirection of rotation of said rotatable member, means including a rstand a second operating member normally disengaged from said rotatablemember, but movable by said traveling members into engaged drivingrelation with said rotatable member, the first of said operating membersbeing moved into driving relation with said rotatable member by one ofsaid traveling members after a predetermined movement of said travelingmembers in one of said translational directions, the second of saidoperating members being moved into driving relation with said rotatablemember by the other of said traveling members after a predeterminedmovement of said traveling members in the other of said translationaldirections, and switching means operable by said operating members.

4. The combination in a controller operable to perform a controlfunction of driving means including a driving gear, actuating meansincluding a traveling pinion driven by said driving gear, a memberhaving a threaded portion mounting said traveling pinion for rotationaland translational movement thereon, an operating member provided withgear teeth and with a portion from which gear teeth are omitted saidoperating member being moved after a predetermined translationalmovement of said traveling pinion by said traveling pinion intooperating relation with said driving gear, said gear teeth on saidoperating member meshing with said driving gear for movement of saidoperating member independent of said traveling pinion, and switchingmeans operable by said operating member.

5. The combination in a controller operable to perform a controlfunction of driving means including4 a driving gear, actuating meansincluding a traveling pinion driven by said driving gear, a memberhaving a threaded portion mounting said traveling pinion for rotationaland translational movement thereon, an operating member provided withgear teeth and with a portion from which gear teeth are omitted, saidoperating member being mounted for rotation on said mounting member andafter a predetermined translational movement of said traveling pinionbeing movable by said traveling pinion into operating relationship withsaid driving gear for rotation thereby, said gear teeth on saidoperating member meshing with said driving gear for rotating saidoperating member independent of said traveling pinion, and switchingmeans operable by said operating member.

6. The combination in a controller operable to perform a controlfunction of driving means, actuating means including a travelingmember,. means mounting said traveling member for rotational andtranslational movement thereon by said driving means, an operatingmember on said mounting means movable by said traveling member intooperating relation with said driving means for rotation thereby after apredetermined translation of saidv traveling member, said operatingrelation of said operating member and said driving means beingindependent of said traveling member, switching means operable by saidoperating member, and means including said operating vmembers forrotating said mounting means thereby to prevent jamming oi saidcontroller upon overtravel of said driving means.`

7. The combination in a controller operable to perform a controlfunction of driving means in- .ciuding a rotatable member, actuatingmeans including a pair of traveling members driven by said rotatablemember means mounting said traveling members for rotational andtranslational movement respectively in the same direction, saidtraveling members being movable on said mounting. means in one or theother of two predetermined translational directions depending upon thedirection of rotation of said rotatable mem-- ber, means including a rstand a second operating member operable by said traveling members, therst Vof said operating members being movable into operating relationwith said rotatable member by one of said traveling members after apredetermined movement thereof in one of said translational directions,the second of said operating members being movable into operatingrelation with said rotatable member by the other of said travelingmembers after a predetermined movement thereof in the other of saidtranslational directions, said operating relations of said operatingmembers and said rotatable member being independent of said travelingmembers, switching means operable by said operating members, and meansincluding said operating members for rotating said mounting means toavoid further translational movement oi' said traveling members uponovertravel of said rotatable member, said mounting means and saidtraveling members rotating as a unit thereby to prevent Jamming oi' saidcontroller.

8. The combination in a controller operable to perform a controlfunction of driving means including a driving gear, actuating meansincluding a traveling pinion driven by said gear, a member having athreaded portion mounting said traveling pinion for rotational andtranslational movement thereon, an operating member provided-with gearteeth and with a portion from which gear teeth are omitted, saidoperating" member being moved after a predetermined translationalkmovement of said traveling pinion by said traveling pinion intooperating relationship with said driving gear, said gear teeth on saidoperating member meshing with said driving gear for moving saidoperating member independent of said traveling pinion, switching meansoperable by said operating member, and means including said operatingmember and a projection on said mounting member for moving said mountingmember after a predetermined movement of said operating member by saiddriving gear, whereby further translational movement of said travelingpinion is prevented to avoid jamming of the controller upon overtraveLofsaid driving means.

9. The combination in a controller operable to perform a controlfunction-of driving means inmember meshing with said driving gear lforro-v tating said operating member independent of said traveling pinion,switching means operable by said operating member, and means includingsaid operating member and a projection on said mounting member forrotating said mounting member after a `predetermined rotation of saidoperating member bysaid driving gear, whereby v further translationalmovement of said traveling pinion is prevented to avoid jamming of thecontroller upon overtravel of said driving means.

10. The combination in a controller of a normally fixed threaded member,a-travelling gear mounted on said threaded member for rotational andtranslational'movement thereon, a driving gear meshing with saidtravelling gear, an operating gear normally disengaged from said drivinggear mounted to be engaged by said travelling gear after a predeterminedtranslational movement of said travelling gear and moved thereby intoengagement with said driving gear for rotation thereby, and controlmeans actuated by said operating gear. h

ROBERT W. GOFF.

